#include "version.h"

#ifdef USE_CLOUDSKY

#include "wl_def.h"
#include "wl_cloudsky.h"

// Each colormap defines a number of colors which should be mapped from
// the skytable. The according colormapentry_t array defines how these colors should
// be mapped to the wolfenstein palette. The first int of each entry defines
// how many colors are grouped to this entry and the absolute value of the
// second int sets the starting palette index for this pair. If this value is
// negative the index will be decremented for every color, if it's positive
// it will be incremented.
//
// Example colormap:
//   colormapentry_t colmapents_1[] = { { 6, -10 }, { 2, 40 } };
//   colormap_t colorMaps[] = {
//      { 8, colmapents_1 }
//   };
//
//   The colormap 0 consists of 8 colors. The first color group consists of 6
//   colors and starts descending at palette index 10: 10, 9, 8, 7, 6, 5
//   The second color group consists of 2 colors and starts ascending at
//   index 40: 40, 41
//   There's no other color group because all colors of this colormap are
//   already used (6+2=8)
//
// Warning: Always make sure that the sum of the amount of the colors in all
//          color groups is the number of colors used for your colormap!

colormapentry_t colmapents_1[] = { { 16, -31 }, { 16, 136 } };
colormapentry_t colmapents_2[] = { { 16, -31 } };

colormap_t colorMaps[] = {
	{ 32, colmapents_1 },
	{ 16, colmapents_2 }
};

const int numColorMaps = lengthof(colorMaps);

// The sky definitions which can be selected as defined by GetCloudSkyDefID() in wl_def.h
// You can use <TAB>+Z in debug mode to find out suitable values for seed and colorMapIndex
// Each entry consists of seed, speed, angle and colorMapIndex
cloudsky_t cloudSkys[] = {
	{ 626,   800,  20,  0 },
	{ 1234,  650,  60,  1 },
	{ 0,     700,  120, 0 },
	{ 0,     0,    0,   0 },
	{ 11243, 750,  310, 0 },
	{ 32141, 750,  87,  0 },
	{ 12124, 750,  64,  0 },
	{ 55543, 500,  240, 0 },
	{ 65535, 200,  54,  1 },
	{ 4,     1200, 290, 0 },
};

byte skyc[65536L];

long cloudx = 0, cloudy = 0;
cloudsky_t *curSky = NULL;

static int GetCloudSkyDefID()
{
	int skyID;
	switch(gamestate.episode * 10 + mapon)
	{
		case  0: skyID =  0; break;
		case  1: skyID =  1; break;
		case  2: skyID =  2; break;
		case  3: skyID =  3; break;
		case  4: skyID =  4; break;
		case  5: skyID =  5; break;
		case  6: skyID =  6; break;
		case  7: skyID =  7; break;
		case  8: skyID =  8; break;
		case  9: skyID =  9; break;
		default: skyID =  9; break;
	}
	assert(skyID >= 0 && skyID < lengthof(cloudSkys));
	return skyID;
}

void SplitS(unsigned size,unsigned x1,unsigned y1,unsigned x2,unsigned y2)
{
if(size==1) return;
if(!skyc[((x1+size/2)*256+y1)])
{
	skyc[((x1+size/2)*256+y1)]=(byte)(((int)skyc[(x1*256+y1)]
			+(int)skyc[((x2&0xff)*256+y1)])/2)+rand()%(size*2)-size;
	if(!skyc[((x1+size/2)*256+y1)]) skyc[((x1+size/2)*256+y1)]=1;
}
if(!skyc[((x1+size/2)*256+(y2&0xff))])
{
	skyc[((x1+size/2)*256+(y2&0xff))]=(byte)(((int)skyc[(x1*256+(y2&0xff))]
			+(int)skyc[((x2&0xff)*256+(y2&0xff))])/2)+rand()%(size*2)-size;
	if(!skyc[((x1+size/2)*256+(y2&0xff))])
		skyc[((x1+size/2)*256+(y2&0xff))]=1;
}
if(!skyc[(x1*256+y1+size/2)])
{
	skyc[(x1*256+y1+size/2)]=(byte)(((int)skyc[(x1*256+y1)]
			+(int)skyc[(x1*256+(y2&0xff))])/2)+rand()%(size*2)-size;
	if(!skyc[(x1*256+y1+size/2)]) skyc[(x1*256+y1+size/2)]=1;
}
if(!skyc[((x2&0xff)*256+y1+size/2)])
{
	skyc[((x2&0xff)*256+y1+size/2)]=(byte)(((int)skyc[((x2&0xff)*256+y1)]
			+(int)skyc[((x2&0xff)*256+(y2&0xff))])/2)+rand()%(size*2)-size;
	if(!skyc[((x2&0xff)*256+y1+size/2)]) skyc[((x2&0xff)*256+y1+size/2)]=1;
}

skyc[((x1+size/2)*256+y1+size/2)]=(byte)(((int)skyc[(x1*256+y1)]
		+(int)skyc[((x2&0xff)*256+y1)]+(int)skyc[(x1*256+(y2&0xff))]
		+(int)skyc[((x2&0xff)*256+(y2&0xff))])/4)+rand()%(size*2)-size;

SplitS(size/2,x1,y1+size/2,x1+size/2,y2);
SplitS(size/2,x1+size/2,y1,x2,y1+size/2);
SplitS(size/2,x1+size/2,y1+size/2,x2,y2);
SplitS(size/2,x1,y1,x1+size/2,y1+size/2);
}

void InitSky()
{
	unsigned cloudskyid = GetCloudSkyDefID();
	if(cloudskyid >= lengthof(cloudSkys))
		I_FatalError("Illegal cloud sky id: %u", cloudskyid);
	curSky = &cloudSkys[cloudskyid];

	memset(skyc, 0, sizeof(skyc));
	// funny water texture if used instead of memset ;D
	// for(int i = 0; i < 65536; i++)
	//     skyc[i] = rand() % 32 * 8;

	srand(curSky->seed);
	skyc[0] = rand() % 256;
	SplitS(256, 0, 0, 256, 256);

	// Smooth the clouds a bit
	for(int k = 0; k < 2; k++)
	{
		for(int i = 0; i < 256; i++)
		{
			for(int j = 0; j < 256; j++)
			{
				int32_t val = -skyc[j * 256 + i];
				for(int m = 0; m < 3; m++)
				{
					for(int n = 0; n < 3; n++)
					{
						val += skyc[((j + n - 1) & 0xff) * 256 + ((i + m - 1) & 0xff)];
					}
				}
				skyc[j * 256 + i] = (byte)(val >> 3);
			}
		}
	}

	// the following commented line could be useful, if you're trying to
	// create a new color map. This will display your current color map
	// in one (of course repeating) stripe of the sky

	// for(int i = 0; i < 256; i++)
	//     skyc[i] = skyc[i + 256] = skyc[i + 512] = i;

	if(curSky->colorMapIndex >= lengthof(colorMaps))
		I_FatalError("Illegal colorMapIndex for cloud sky def %u: %u", cloudskyid, curSky->colorMapIndex);

	colormap_t *curMap = &colorMaps[curSky->colorMapIndex];
	int numColors = curMap->numColors;
	byte colormap[256];
	colormapentry_t *curEntry = curMap->entries;
	for(int calcedCols = 0; calcedCols < numColors; curEntry++)
	{
		if(curEntry->startAndDir < 0)
		{
			for(int i = 0, ind = -curEntry->startAndDir; i < curEntry->length; i++, ind--)
				colormap[calcedCols++] = ind;
		}
		else
		{
			for(int i = 0, ind = curEntry->startAndDir; i < curEntry->length; i++, ind++)
				colormap[calcedCols++] = ind;
		}
	}

	for(int i = 0; i < 256; i++)
	{
		for(int j = 0; j < 256; j++)
		{
			skyc[i * 256 + j] = colormap[skyc[i * 256 + j] * numColors / 256];
		}
	}
}

// Based on Textured Floor and Ceiling by DarkOne
void DrawClouds(byte *vbuf, unsigned vbufPitch, int min_wallheight)
{
	// Move clouds
	fixed moveDist = tics * curSky->speed;
	cloudx += FixedMul(moveDist,finesine[curSky->angle>>ANGLETOFINESHIFT]);
	cloudy -= FixedMul(moveDist,finecosine[curSky->angle>>ANGLETOFINESHIFT]);

	// Draw them
	int y0, halfheight;
	unsigned top_offset0;
	fixed dist;                                // distance to row projection
	fixed tex_step;                            // global step per one screen pixel
	fixed gu, gv, du, dv;                      // global texture coordinates
	int u, v;                                  // local texture coordinates

	// ------ * prepare * --------
	halfheight = viewheight >> 1;
	y0 = min_wallheight >> 3;                  // starting y value
	if(y0 > halfheight)
		return;                                // view obscured by walls
	if(!y0) y0 = 1;                            // don't let division by zero
	top_offset0 = vbufPitch * (halfheight - y0 - 1);

	// draw horizontal lines
	for(int y = y0, top_offset = top_offset0; y < halfheight; y++, top_offset -= vbufPitch)
	{
		dist = (heightnumerator / y) << 8;
		gu =  viewx + FixedMul(dist, viewcos) + cloudx;
		gv = -viewy + FixedMul(dist, viewsin) + cloudy;
		tex_step = (dist << 8) / viewwidth / 175;
		du =  FixedMul(tex_step, viewsin);
		dv = -FixedMul(tex_step, viewcos);
		gu -= (viewwidth >> 1)*du;
		gv -= (viewwidth >> 1)*dv;          // starting point (leftmost)
		for(int x = 0, top_add = top_offset; x < viewwidth; x++, top_add++)
		{
			if(wallheight[x] >> 3 <= y)
			{
				u = (gu >> 13) & 255;
				v = (gv >> 13) & 255;
				vbuf[top_add] = skyc[((255 - u) << 8) + 255 - v];
			}
			gu += du;
			gv += dv;
		}
	}
}

#endif
